ANALYSIS OF WIND-DRIVEN GRID CONNECTED INDUCTION GENERATORS UNDER UNBALANCED GRID CONDITIONS

Wind driven induction generator feeding power to the grid has been ana lyzed under the abnormal condition of unbalanced grid voltages. Using the symmetrical component and double revolving field theory, appropria te equivalent circuits and model equations have been derived for the g enerating mode with suitable realistic modifications. It is emphasized that the active and reactive power components and their directions fo r both positive and negative sequence systems need to be properly iden tified in order to obtain the cumulative response of the generator und er different wind power conditions. In view of the fact that the react ive power is drawn from the grid while the active power is fed into th e grid, the extent of variations in power fed to the grid and the reac tive VAR due to unbalanced grid voltages for different wind power cond itions need to be estimated to provide guidelines in the design and op eration of wind energy conversion system. Both experimental and theore tical results for a 3.7 kW laboratory model have also been presented, to validate the theoretical formulations, extendable to large units. E xtensive data have been presented and discussed for a 55 kW unit insta lled in site.